Audio falling behind capture card recording

[TheRhysWyrill]

Okay so i've been having this problem for a few weeks now & i'm at a loss with what could be causing it, basically i record console gameplay & use Audacity to record my commentary at the same time, there is always only around 1 second difference between the 2 to begin with, however the longer the session goes on the more i can notice the audio falling behind the video, the most bizarre thing about this issue is if i use my built in mic to record (Which isn't an option) it's perfectly fine, what i use instead is a simple USB soundcard, it was working fine a few weeks ago & since then nothing has changed that i can think of that could be causing this issue, if anyone has any idea what could be causing this issue please help it would be greatly appreciated.

Thanks

[Trebor]

... the longer the session goes on the more i can notice the audio falling behind the video

Sounds like Skipping : tiny almost unnoticeable pieces of audio are occasionally missing [dropped] . As time goes on the little pieces add up , so the tracks become increasingly out-of-sync. Possible solutions to skipping are listed here ... http://manual.audacityteam.org/o/man/fa ... mall_skips[/b]_or_duplications.3F

[DVDdoug]

...there is always only around 1 second difference between the 2 to begin with

That would be explained by the two applications using different buffer sizes. I would guess if the audio/video recorder has a bigger buffer (for a couple of reasons) and that would cause the game recording to lag behind the Audacity recording.

...however the longer the session goes on the more i can notice the audio falling behind the video, the most bizarre thing about this issue is if i use my built in mic to record (Which isn't an option) it's perfectly fine, what i use instead is a simple USB soundcard, it was working fine a few weeks ago & since then nothing has changed that i can think of...

Other than the fact that is was working OK... Another possibility is this - Every device has its own clock (oscillator) controlling the sample rate (i.e. 44.1kHz). No two clocks are exactly the same. Over time, they WILL drift apart.

If you have two high quality devices (such as a "prosumer" audio interface and a high quality podcast mic), or if you are just lucky and the two devices have well-matched clocks, it may be several hours before they drift-apart noticeably.

Pros use a very accurate master clock and interfaces with a master clock interface to keep everything locked in sync.

[TheRhysWyrill]

...there is always only around 1 second difference between the 2 to begin with

That would be explained by the two applications using different buffer sizes. I would guess if the audio/video recorder has a bigger buffer (for a couple of reasons) and that would cause the game recording to lag behind the Audacity recording.

What i meant by the 1 second difference is that's due to me taking one second to go from clicking record on the capture card software & then to click the record button on Audacity, sorry for not making that clear.

[Gale Andrews]

Are you still on Windows 8.1 and Audacity 2.0.6? It always helps us to know.

...there is always only around 1 second difference between the 2 to begin with

That would be explained by the two applications using different buffer sizes. I would guess if the audio/video recorder has a bigger buffer (for a couple of reasons) and that would cause the game recording to lag behind the Audacity recording.

What i meant by the 1 second difference is that's due to me taking one second to go from clicking record on the capture card software & then to click the record button on Audacity, sorry for not making that clear.

But that was always the case wasn't it?

If the recordings used not to drift further apart using the same USB sound card, think about anything that might have changed. Sample rate differences can cause drift. Did you change the Audacity project rate or the capture software sample rate?

On what sound device is the game audio playing exactly? If you play the audio on the same device as the device that is recording the audio, you may avoid different clock speeds. For example, playing and recording on a USB headset, playing on a USB sound card and connecting a hardwired mic to that, or playing on the motherboard sound card and connecting a hardwired mic to that are all examples of using the same sound device for playback and recording.

On the other hand a USB mic (unless it has a headphones port that accepts audio from the computer) would be a separate device, so would be a poor choice for synchronizing audio.

If you don't get the sync problem with the internal mic, try using an external hardwired mic connected to the motherboard sound card.


Gale

[cyrano]

What i meant by the 1 second difference is that's due to me taking one second to go from clicking record on the capture card software & then to click the record button on Audacity, sorry for not making that clear.

Are you really, really sure you should click "record" in both places?

I've never known that to work. There's always a first, tho

It felt like clock drift to me, until I saw your quoted text above.

[TheRhysWyrill]

Are you still on Windows 8.1 and Audacity 2.0.6? It always helps us to know.

...there is always only around 1 second difference between the 2 to begin with

That would be explained by the two applications using different buffer sizes. I would guess if the audio/video recorder has a bigger buffer (for a couple of reasons) and that would cause the game recording to lag behind the Audacity recording.

What i meant by the 1 second difference is that's due to me taking one second to go from clicking record on the capture card software & then to click the record button on Audacity, sorry for not making that clear.

But that was always the case wasn't it?

If the recordings used not to drift further apart using the same USB sound card, think about anything that might have changed. Sample rate differences can cause drift. Did you change the Audacity project rate or the capture software sample rate?

On what sound device is the game audio playing exactly? If you play the audio on the same device as the device that is recording the audio, you may avoid different clock speeds. For example, playing and recording on a USB headset, playing on a USB sound card and connecting a hardwired mic to that, or playing on the motherboard sound card and connecting a hardwired mic to that are all examples of using the same sound device for playback and recording.

On the other hand a USB mic (unless it has a headphones port that accepts audio from the computer) would be a separate device, so would be a poor choice for synchronizing audio.

If you don't get the sync problem with the internal mic, try using an external hardwired mic connected to the motherboard sound card.


Gale

I'm on Windows 10 now using Audacity 2.1.1 however i was encountering this problem before i updated, i've not changed anything in Audacity from what i'd normally use, i would use the internal mic port but because i have a combo jack (Both a headphone & mic port combined into one) I have to use a Y splitter which for some reason causes audio to 'leak' on to the microphone track regardless of how quiet i make the audio going into my headphones which is why i went for using a USB soundcard.

The audio plays through the capture card software so that may explain why i don't run into that issue when using the internal mic, what i'll try later today is connecting both devices so that they play through the USB soundcard & see how that goes.

[Gale Andrews]

What i meant by the 1 second difference is that's due to me taking one second to go from clicking record on the capture card software & then to click the record button on Audacity, sorry for not making that clear.

Are you really, really sure you should click "record" in both places?

I've never known that to work. There's always a first, tho

Users recording video commentary often do that. That's why we get so many requests that Audacity should support "global shortcuts" that work whatever app you're in.


Gale

[cyrano]

Users recording video commentary often do that. That's why we get so many requests that Audacity should support "global shortcuts" that work whatever app you're in.

Recording with two different interfaces on the same computer is a Very Bad Idea™.

Those two inputs use different clocks*. The resulting drift won't be too bad if you only record short clips. It will be very unpredictable and will drift a lot with longer recordings.

In this case, I'd first look at the video settings. Changing frame rate can make drift a lot worse or better. And it used to work in this case. Try 29.96 fps in stead of 30 or vice versa. I suppose the video capture card also does audio at 48 KHz. Make sure both recording programs us the same bitrate (48 KHz preferably as the final result is video).

*Unless it's professional gear with a separate sync or clock connection.

[TheRhysWyrill]

Users recording video commentary often do that. That's why we get so many requests that Audacity should support "global shortcuts" that work whatever app you're in.

Recording with two different interfaces on the same computer is a Very Bad Idea™.

Those two inputs use different clocks*. The resulting drift won't be too bad if you only record short clips. It will be very unpredictable and will drift a lot with longer recordings.

In this case, I'd first look at the video settings. Changing frame rate can make drift a lot worse or better. And it used to work in this case. Try 29.96 fps in stead of 30 or vice versa. I suppose the video capture card also does audio at 48 KHz. Make sure both recording programs us the same bitrate (48 KHz preferably as the final result is video).

*Unless it's professional gear with a separate sync or clock connection.

It can't be that bad of an idea if it had been working perfectly for over a year, it's only until recently that they have started to drift apart from one another, if i use a separate audio recording program however it still drifts apart but it doesn't occur until much later.